Broach.



B. SLAPAK.

BROAOH.

APPLIOATION FILED OCT. 2, 1909.

Patented June 20, 1911.

number of tools required.

unrrnn s ratus rarnn r or EMIL- SLAPAK, O13 CLEVELAND, 01-110.

BROACH.

fi'pevificetion of Letters Patent Patented June 5 3d. 1911.

Application filed October 2, 1909. Serial No. 520,733.

the same.

. This invention relates to improvements in breaches or broaching tools,and particularly to brooches designed for converting circular openingsto polygonal openings, such as square hexagonal and octagonal openings.

Heretolfore circular openings have been converted to polygoi'nilopenings either by filing in the sides of the polygon or by driv ingthrough the circular opening a series of breaching tools each ofpolygonal shape and of gradually inciwasing sizes. Both of the abovemethods are unsatisfactory and expensive because oi. the time requiredin forming the polygonal openings or the large I urthermore the openingsare frequently not accurately :f'ormed particularly when formed by filinThe object of the present invention is the provision of a. broach whichis inexpensive to manufacture and which is so constructed that whendriven through a circular opening by one operation forms a polygonalopening with great accuracy.

In carrying out my invention 1 provide a broach comprising a bodyportion which is provided with a series of alternately arrangedshoulders and recesses extending about the body portion, the shoulder:having a series of Hot il'accs corresponding in number and ar 'augemcntto the tacos of the polygonal opening which is to be formed, and thefaces of the diilcrent shoulders being of successively increasing lengthuntil at the last or final shoulder the llat. 'laces merge forming thecorners of a polygon.

More specifically considered the invention relates to a broach having atone end a shank adapted to be gripped by a clutch or similar holdingdevice of a suitahle press and having a body-portion which is :lorlncdfrom 'apered stock circular in cross section, the

' body portion being provided with a series of alternately z'lrraugedshoulders and recesses spaced lengthwise thereof, the lowermost shoulderbeing preferably circular in cross section and of a diameter slightlyless than the diameter of the circular opening, and each of theremaining shoulders having a cutting edge and a series of tlat facescorresponding in number and arrangement to the sides of the polygon andhaving between the flat faces arc-shaped portions, the flat faces of thedilfercnt shoulders being of gradually increasing length and theareshaped portions of the different shoulders being of graduallydecreasing length but of increasing radius until at the last or finalshoulder the flat faces merge forming the corners of the polygon.

My inventiol'i may be further briefly summarized as consisting incertain novel details of construction which will be described in thespecification and set forth in the appended claims.

For an understanding of my invention reference is had to theaccompanying sheet of d -a'wings wherein" l igure 1 is a side elevationof a broach which is utilized for converting a circular opening to asquare opening. Fig. 2 is a view of same rotated on its longitudinalaxis through an arc of 45. Fig. is an eleva tion of a breach which isutilized for converting a circular opening to a hexagonal opening. Figs.4, 5 and 6 are transverse sectional views along the lines. 4-4, 5-5 andt$-6, respertively of Fig. 1, looking in the direction indicated by thearrows. Figs. 7, 8, 9 and 10 are transverse sectional views along thelines 7-7, 8-8, 9-4) and 10-10, respectively, of Fig. looking in thedirection indicated by the arrows.

Referring now to Figs. 1 2, i 5 and (3 showing a broach for forming asquare opening, 8 the .broach tion. The secured in press, such and 9represents the body por shank portion is designed to be a clutch orsimilar portion of a as a mandrel press, when it is desired to form asquare opening from a circular opening in metal or stock. At its lowerend the bofdy=portion is circular in cross section. 'and the diameterthereof is substantially the same or slightly less than the diameter ofthe circular opening which is to be converted to the square opening. Thebody portion atits upper end is square in cross section the length ofeach side being equal to the diameter 01 the lower end of the bodyportion. The body portion 9 is represents the shank portion otprovidedwith a series of alternately arranged shoulders 12 and recesses 13extending about the body portion andspaced longitudinally thereof. Allthe shoulders are provided with lower cutting edges 14 and may thereforebe termed cutting shoulders.

These cutting shoulders are each provided with four fiat faces 15 whichcorrespond in number and arrangement to the sides of the square and areof increasing length on the different shoulders from the lowermostcutting shoulder to the uppermost. These flat faces are formed byplaning or otherwise forming on the body portion of the broach foursides or faces which coincide with the sides of the square, the oppositesides being arallel to each other and to the axis of the roach. Locatedbetween the flat faces 15 of each shoulder are four 'arc-shaped portionsor faces 16. These arc-shaped portions of the different shoulders are ofgradually decreasing length from the lowermost cutting shoulder to theuppermost shoulder and are of gradually increasin radius. The arc-shapedportions on each sioulder overhang slightly the arc-shaped portion: onthe shoulder just beneath and thereby form cutting edges, as shownclearly in the transverse sectional views. At the uppermost shoulder theflat faces merge, as shown most clearly in Figs. 5 and 6, forming thecorners 17 of the square.

' Referring now to Figs. 3, 7, 8, 9 and 10,

wherein I have shown a broach for forming a hexagonal opening, it willbe seen that I have here shown a broach, the principal, general featuresof the design, bud manner of construction are substantially the same asthose first described. This broach has a shanks portion 8 and a bodyportion 9. The body portion i.-. provided'with alternately arranged-shoulders 12 having cutting edges 14 and annular recesses 13'.

The cutting shoulders are each provided,

- the uppermost shoulder the flat faces merge forming the six corners 17of the hexagon, these corners being shown clearly in the sectionalviews.

,lIt will be seen that I have provided a tool, which, althoughinexpensive to manufacture, will convert a circular opening to apolygonal opening having any 'number of sides very quickly and withoutrequiring the expenditure of a great deal of time as with the methodsheretofore employed. All that is necessary is to place the broach in asuitable press .and then lower the. same through ,the circular openingin the stock, the polyg-.

onal opening belng formed by a single stroke of the tool, and, as thetool is forced through the circular opening, the latter is graduallyconverted to the polygonal shape, the lower edges of. the shouldersgradually cutting away the material and-forming the corners. Thematerial which is removed by these cutting edges of the shoulders passesto the recesses between the shoulders, and thus does not interfere withthe cutting operation. It will be understood, of course,- that thebroach may have any number of sides or faces and may be utilized forforming polygonal openings of any number of sides. a

What I claim is, o

1. A broach for converting a circular opening to polygonal openingcomprising a body portion having a series of shoulders and annularrecesses spaced lengthwise thereof, said shoulders having cutting edgesand having flat faces corresponding'in number and arrangement to thesides of the polygonal openin to be formed and all but the last or finalshoulder having arc-shaped portions between the flat faces, the flatfaces of the different shoulders being of gradually v increasing lengthfrom the lowermost shoulder to the uppermost shoulder until at theuppermost shoulder the faces merge forming the corners of a polygon, andthe arcshaped portions of the diiferentshoulders being of graduallydecreasing length but of increasing radius from the lowermost shoulderupwardly. v

2. A breach for converting a. circular opening to a polygonal openincomprising a body portion circular incross section at its lower end andhaving-a shank at its up; per end and provided intermediate of the shankand lower end with a series of shoulders and recesses spaced lengthwisethereof, said shoulders having cutting edges and havmg flat facesCQII'GSPOIIdIII in number and arrangement to the sides of the polygo- Inal opening which is to be formed and all but the last or final shoulderhaving arcshaped portions between the fiatfaces, the

fiat faces of the different shoulders being of gradually increasinglength from the lOW6f-' most shoulder to the uppermost shoulder until atthe uppermost shoulder thefaces 'Inerge forming the corners of a polgen,

and the arc-shaped ortions of the di erent' shoulders being 0 graduallydecreasing length but of increasing radius from the lowermost shoulderupwardly.

3. A broach for converting a circular opening to a polygonal opening,comprising a body portion having a shank at its upper end, and providedintern'iediate of the shank and lower end with a series of shouldershavin cutting edges, and having straight faces corresponding in numberand arrangement to the sides of the polygonal opening which is to beformed, and having arcshaped portions between the straightfaces, thestraight faces of the ilil'l'erent shoulders 10 being of graduallyincreasing length from the lowermost shoulder to the uppermost shoulder,and the aro-sliapesl po ions of the different shoulders being; ofgradually decreasing length but of increasing radius from the lowermostshoulder upwardly.

In testimony whereof I sign the foregoing specification, in the presenceof two witmesses.

EMIL SLAPAK. \Vifncsses:

V'io'ron C. LYNCH, N. L. McDoNnnLL.

